Well, I just bought a $630,000 house. So for me, those numbers would come out to...
1) $189,000 needed per year.
2) $4,725,000 net worth requirement.
Those numbers are nowhere close. For awhile, my goal had been for FireCalc to say that I had a ~95% chance of making it on $60,000 per year, and to have investible assets of around $2M. But, after I bought the house, that all went out the window, as my mortgage payment is about $2940 per month.
Anyway, at this point, once I got to $2M, I don't think I'd pull the plug just yet. I had actually gotten within spitting distance of that back in August/early September, but like other goals in the past, once it came within reach, it suddenly didn't seem so lofty. And after making the down payment on the house, and then the stock market hiccups in October and December, and the furlough that put me out of work for five weeks, it was a wakeup call that I wasn't as ready as I thought I'd be.
I really haven't put too much thought, since I bought the house, on what my exact number would be. I have a feeling $3M would definitely do it for me. That would be $90-120K in income shooting for a 3-4% withdrawal rate (and not even accounting for SS). I don't even make $90K at my j*b, so I'm pretty sure I'd be happy with that range. This is vague, I know, but I guess somewhere between $2M and $3M NW would do the trick for me.